Danny Murphy
Host nation: Qatar Dates: 20 November-18 December Coverage: Live on BBC TV, BBC iPlayer, BBC Radio 5 Live, BBC Radio Wales, BBC Radio Cymru, BBC Sounds and the BBC Sport website and app. Day-by-day TV listings - Full coverage details

At the World Cup, fitness and athletic ability are more important than technical ability.

The teams who caused upsets also had a very good tactical plan, which is one of the reasons we saw so many shocks.

The physical output we saw from Japan when they beat Spain and Germany and Saudi Arabia when they beat Argentina, helped them overcome teams who, on paper, had better players.

The more technical side would usually wear the opposition down by the end of the game, with more spaces appearing when they tire late on.

Manchester City scored more goals in the last 15 minutes of games than any other team in the league last season.

It has been different in the country. The key moments in games have been in the second half.

The new rule that allows teams to make five substitution instead of three definitely helps.

In the middle of matches, football is a squad game.

South Korea's amazing late success over Portugal was another completely unexpected result, but it was a substitute who scored their injury time winner.

The most important World Cup ever for substitutes

The new five substitution rule is a good idea because of the amount of games and the intensity of football.

When people talk about it, they look at it from the point of view that it benefits the bigger team because they have better players to bring on.

If you bring good players on, then you have to bring good players off, and the best players are usually on the pitch from the beginning.

The destructive side of football is easier to create than to create, and being able to make five changes helps the side do more defending and running. It works better for them.

If your players are tired and have been chasing the ball all game, you can replenish the energy in key areas in the middle of the field to keep your intensity high.

It's up to all the coaches to use what they have on the bench to make an impact, whether it is by trying to be more brave or by maintaining your defensive stability.

Making the right changes at the right times is more important than ever, and I think substitute players will be more important than ever in the knockout stage.

Underdogs are using their brains too

There is a wonderful desire from some of the underdogs at the World Cup to give everything.

If you have the right personnel you can play high-tempo football.

There is no way that Canada should have dominated this side. The same can be said for Morocco, who have some good players, but they are also strong.

England have some fantastic technical players who are good runners, but when they played the United States, they were up against an athletic middle.

Weston McKennie, Tyler Adams and Yunus Musah were in the middle of the pitch and at the center of the plan.

They were able to stop them from playing because they are not better than England'sMidfielders.

I want to make it clear that these teams are more than just a bunch of chickens. It's not just down to them playing at 100mph that they're successful.

One of the clever things I've seen with some of the sides who have gotten a surprise result is that they know when to take a break.

While it was Japan's high press that got them back in the game against Spain, and they were still making runs in behind Germany's defence late on in that game, they did both things in spurts. The coach has to make that decision.

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Will the shocks continue in the knockout stage?

There was a realization as the group stage went on that teams with good physical strength and athletes with determination had to be matched.

Although Spain were an exception to the rule, some teams with more technical players altered their approach if they could equal their work rate.

The only ones in the country that rely on technical ability are Spain and France. You wouldn't call the two young boys supreme athletes because they can run ahead of Busquets.

When they play Morocco in the last 16 they will try to dominate them like they try to dominate all their opponents.

Everyone else will make sure there is a lot of legs in their team. Raphinha plays for them because he never stops running, and Richarlison plays for them because of his work-rate.

The element of surprise that some of the lesser-known players had early on is gone now as we head into the last 16.

I would expect more surprises from now on, as Japan are a wonderful team with wonderful togetherness.

England got kicked up the backside with their draw against the US. I think it's a good thing that they didn't just breeze through all of their games. It means they will be prepared.

Danny Murphy was talking to someone in the Middle East.

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